<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>计算器</title>
		<style>
			table{
				width:400px;
				border-collapse: collapse;
			}
			td{
				width:100px;
				height:100px;
				text-align: center;
			}
			*{
				font-size: 24px;
			}
		</style>
	</head>
	<body>
		<table  border="5">
			<tr >
				<td colspan="4"><input type="number"/></td>
			</tr>
			<tr>
				<td>C</td>
				<td>←</td>
				<td>÷</td>
				<td>*</td>
			</tr>
			<tr>					
				<td>7</td>
				<td >8</td>
				<td>9</td>
				<td>-</td>
			</tr>				
			<tr>
				<td>4</td>
				<td >5</td>
				<td>6</td>
				<td>+</td>
			</tr>
			<tr>
				<td>1</td>
				<td >2</td>
				<td>3</td>
				<td rowspan="2">=</td>
			</tr>
			<tr>
				<td>√</td>
				<td >0</td>
				<td>.</td>
			</tr>		
		</table>
	</body>
</html>
